Arch Linux Security Advisory ASA-201903-6 ========================================= Severity: Medium Date : 2019-03-03 CVE-ID : CVE-2019-1559 Package : lib32-openssl-1.0 Type : information disclosure Remote : Yes Link : https://security.archlinux.org/AVG-918 Summary ======= The package lib32-openssl-1.0 before version 1.0.2.r-1 is vulnerable to information disclosure. Resolution ========== Upgrade to 1.0.2.r-1. # pacman -Syu "lib32-openssl-1.0>=1.0.2.r-1" The problem has been fixed upstream in version 1.0.2.r. Workaround ========== None. Description =========== A padding oracle has been found in OpenSSL versions prior to 1.0.2r. This issue does not impact OpenSSL 1.1.1 or 1.1.0. If an application encounters a fatal protocol error and then calls SSL_shutdown() twice (once to send a close_notify, and once to receive one) then OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. If the application then behaves differently based on that in a way that is detectable to the remote peer, then this amounts to a padding oracle that could be used to decrypt data. In order for this to be exploitable "non-stitched" ciphersuites must be in use. Stitched ciphersuites are optimised implementations of certain commonly used ciphersuites. Also the application must call SSL_shutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). AEAD ciphersuites are not impacted. Impact ====== A remote attacker might be able to use a padding oracle to decrypt confidential data. References ========== https://www.openssl.org/news/secadv/20190226.txt https://security.archlinux.org/CVE-2019-1559